Acceleron Pharma Inc., a biopharmaceutical company, focuses on the discovery, development, and commercialization of therapeutics to treat serious and rare diseases. It offers REBLOZYL, an erythroid maturation agent for the treatment of anemia in adult patients with beta-thalassemia and transfusion-dependent anemia. The company also develops Sotatercept, an activin receptor type IIA fusion protein for the treatment of patients with pulmonary arterial hypertension; ACE-1334, a pulmonary therapeutic candidate that is in Phase I clinical trials; and luspatercept-aamt for non-transfusion-dependent beta-thalassemia patients and lower-risk myelodysplastic syndrome patients. Acceleron Pharma Inc. was formerly known as Phoenix Pharma, Inc. and changed its name to Acceleron Pharma Inc. in February 2004. The company was incorporated in 2003 and is headquartered in Cambridge, Massachusetts. As of November 19, 2021, Acceleron Pharma Inc. operates as a subsidiary of Merck Sharp & Dohme Corp.